India’s rice fields now rank among world’s top methane hotspots

Greenhouse gas (GHG) emissions from paddy fields worldwide have doubled since the 1960s, a new study in NatureFood has found. In the most recent decade, 2011-2020, paddy fields around the world produced around 1.1 billion tonnes of carbon dioxide-equivalent (CO₂-e) emissions every year — a 90.4% increase from the annual emissions between 1961 and 1980, the study reported.

Upon examining the sources contributing to the rise in emissions, the study found that about half the increase was driven by the loss of soil organic carbon. Between 1961 and 1980, paddy fields were soil organic carbon sinks, removing some 289 million tonnes of CO₂-e emissions annually. However, the sink weakened over time. In the 2010s, over a third of paddy fields worldwide in fact began losing carbon from the soil.

Apart from soil organic carbon, methane from paddy fields was also a significant driver of emissions. Flooded fields develop low-oxygen conditions where methane-producing microbes thrive. And paddy fields in eastern India were among the global methane hotspots.